4D95 Diesel Used Engine Blocks For Excavator PC130 - 7 6205 - 21 -
1513
Specification
| Car name: Engine cylinder block |
| Model Number: 4D95 |
| Work form: Turbo |
| Number of Cylinder: 4 |
| Application: Excavator |
| valve: 8 valve |
| Cooling: Water cooling |
| Injection: Direct |
Description
With respect to the engine block, it is essential to adapt its
design, the applied casting process, the selected alloy composition
and heat treatment as well as the method used to ensure an
appropriate cylinder bore surface quality.
Requirements for aluminium engine blocks
The application of aluminium for engine blocks poses a certain
challenge, in particular with respect to diesel engines. The
required rigidity and strength, the realisation of a reliable
bolting concept for the cylinder head and the main bearings as well
as the resulting increase of the crankshaft clearances and the
inferior acoustics require specific solutions. On the other hand,
an aluminium engine block benefits not only from the lower density
compared to grey cast iron, but also from the high specific modulus
of elasticity and the very good heat conductivity.
1. Thermal conductivity
Modern aluminium engine blocks "see" temperatures of 150°C in
crank-shaft bearings and up to 200°C in the inter-bore regions. The
high thermal conductivity of cast aluminium alloys ensures
efficient heat dissipation into the coolant.
2. Strength at elevated temperatures
An adequate static strength level up to temperatures of 150°C (oil
temperature) is required mainly in the joint face with the cylinder
head due to the load of the head bolts and in the bearing saddles
to withstand the forces coming from the crankshaft rotation and the
thermal expansion of the engine block.
3. Strength / hardness at room temperature
A minimum room temperature strength / hardness of the aluminium
alloy is necessary to ensure good machinability (depending on the
machining parameters) and for assembly.
4. Fatigue strength
During operation of the engine, the engine block is subjected to
cyclic tensile stress in a wide temperature region ranging from sub
zero temperatures (when the engine is started in the winter) to
elevated temperatures corresponding to the oil temperature of about
150°C. A most important material characteristic for engine block
design is therefore the fatigue strength.
